{$thread['subject']} for username?

[LowPriceBargains]

Hello i'm not sure what these ({$thread['subject']}) are called but is there one so i can have the current user's name in the style it is in a thread or on the whos online section.
also what are these {$thread['subject']} called?
Thank you

[Yaldaram]

$thread['subject'] means like this thread's title. "[General] {$thread['subject']} for username?"

For username, the variable used is;

{$thread['username']}

[LowPriceBargains]

I mean so i can use it in a custom file but i figured this

$name = format_name($mybb->user['username'], $mybb->user['usergroup']);